[llvm] [AArch64][PAC] Mark $Scratch operand of AUTxMxN as earlyclobber (PR #173999)

[Anatoly Trosinenko via llvm-commits]

atrosinenko wrote:

Added a test case checking that MIR output for `AUTxMxN` instruction contains `early-clobber` in its list of output operands in 1b35218f935a9b31d92700ecf9ae3d1cccc32a12.

https://github.com/llvm/llvm-project/pull/173999